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Title: PERCEPTION AND DISPLAYS FOR TELEOPERATED ROBOTS.
Creator: Upham Ellis, Linda, Sims, Valerie, University of Central Florida
Abstract / Description: In remote or teleoperational tasks involving humans and robots, various aspects of the remote display system may greatly influence the individual's interactions with the teleoperated entity. This dissertation examined various configurations of display systems on several measures of operator performance, physiological states, and perceptions of the task. Display configurations included altering the camera placement (attached to the robot or placed overhead), screen orientation (horizontal...
Show moreIn remote or teleoperational tasks involving humans and robots, various aspects of the remote display system may greatly influence the individual's interactions with the teleoperated entity. This dissertation examined various configurations of display systems on several measures of operator performance, physiological states, and perceptions of the task. Display configurations included altering the camera placement (attached to the robot or placed overhead), screen orientation (horizontal or vertical), and screen size (small or large). Performance was measured in terms of specific task goals, accuracies, strategies, and completion times. Physiological state was assessed through physiological markers of arousal, specifically heart rate and skin conductance. Operator perception of the task was measured with a self-reported perception of workload and frustration. Scale model live simulation was used to create a task driven environment to test the display configurations. Screen size influenced performance on complex tasks in mixed ways. Participants using a small screen exhibited better problem solving strategies in a complex driving task. However, participants using the large screen exhibited better driving precision when the task required continual attention. These findings have value in design decisions for teleoperated interfaces where the advantages and disadvantages of screen size must be considered carefully. Orientation of the visual information seems to have much less impact on the operator than the source of the information, though it was an important factor of the display system when taken together with screen size and camera view. Results show strong influence of camera placement on many of the performance variables. Interestingly, the participants rated a higher frustration in the overhead condition, but not a higher task load, indicating that while they realized that the task was frustrating and perhaps they could have done better, they did not recognize the task as overloading. This was the case even though they took longer to complete the task and experienced more errors related to turning in the overhead camera condition. This finding may indicate a potential danger for systems in which the operator is expected to recognize when he or she is being overloaded. This type of performance decrease due to added frames of reference may be too subtle to register in the operator's self awareness
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Date Issued: 2008
Identifier: CFE0002330, ucf:47818
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0002330

Title: HIGH QUALITY GATE DIELECTRIC/MoS2 INTERFACES PROBED BY THE CONDUCTANCE METHOD.
Creator: Krishnaprasad Sharada, Adithi Pandrahal, Roy, Tania, Abdolvand, Reza, Yuan, Jiann-Shiun, University of Central Florida
Abstract / Description: Two-dimensional materials provide a versatile platform for various electronic and optoelectronic devices, due to their uniform thickness and pristine surfaces. We probe the superior quality of 2D/2D and 2D/3D interfaces by fabricating molybdenum disulfide (MoS2)-based field effect transistors having hexagonal boron nitride (h-BN) and Al2O3 as the top gate dielectrics. An extremely low trap density of ~7x10^10 states/cm2-eV is extracted at the 2D/2D interfaces with h-BN as the top gate...
Show moreTwo-dimensional materials provide a versatile platform for various electronic and optoelectronic devices, due to their uniform thickness and pristine surfaces. We probe the superior quality of 2D/2D and 2D/3D interfaces by fabricating molybdenum disulfide (MoS2)-based field effect transistors having hexagonal boron nitride (h-BN) and Al2O3 as the top gate dielectrics. An extremely low trap density of ~7x10^10 states/cm2-eV is extracted at the 2D/2D interfaces with h-BN as the top gate dielectric on the MoS2 channel. 2D/3D interfaces with Al2O3 as the top gate dielectric and SiOx as the nucleation layer exhibit trap densities between 7x10^10 and 10^11 states/cm2-eV, which is lower than previously reported 2D-channel/high-k-dielectric interface trap densities. The comparable values of trap time constants for both interfaces imply that similar types of defects contribute to the interface traps. This work establishes the case for van der Waals systems where the superior quality of 2D/2D and 2D/high-k dielectric interfaces can produce high performance electronic and optoelectronic devices.
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Date Issued: 2018
Identifier: CFE0007214, ucf:52209
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007214

Title: Exploring Natural User Abstractions For Shared Perceptual Manipulator Task Modeling (&) Recovery.
Creator: Koh, Senglee, Laviola II, Joseph, Foroosh, Hassan, Zhang, Shaojie, Kim, Si Jung, University of Central Florida
Abstract / Description: State-of-the-art domestic robot assistants are essentially autonomous mobile manipulators capable of exerting human-scale precision grasps. To maximize utility and economy, non-technical end-users would need to be nearly as efficient as trained roboticists in control and collaboration of manipulation task behaviors. However, it remains a significant challenge given that many WIMP-style tools require superficial proficiency in robotics, 3D graphics, and computer science for rapid task modeling...
Show moreState-of-the-art domestic robot assistants are essentially autonomous mobile manipulators capable of exerting human-scale precision grasps. To maximize utility and economy, non-technical end-users would need to be nearly as efficient as trained roboticists in control and collaboration of manipulation task behaviors. However, it remains a significant challenge given that many WIMP-style tools require superficial proficiency in robotics, 3D graphics, and computer science for rapid task modeling and recovery. But research on robot-centric collaboration has garnered momentum in recent years; robots are now planning in partially observable environments that maintain geometries and semantic maps, presenting opportunities for non-experts to cooperatively control task behavior with autonomous-planning agents exploiting the knowledge. However, as autonomous systems are not immune to errors under perceptual difficulty, a human-in-the-loop is needed to bias autonomous-planning towards recovery conditions that resume the task and avoid similar errors.In this work, we explore interactive techniques allowing non-technical users to model task behaviors and perceive cooperatively with a service robot under robot-centric collaboration. We evaluate stylus and touch modalities that users can intuitively and effectively convey natural abstractions of high-level tasks, semantic revisions, and geometries about the world. Experiments are conducted with `pick-and-place' tasks in an ideal `Blocks World' environment using a Kinova JACO six degree-of-freedom manipulator. Possibilities for the architecture and interface are demonstrated with the following features; (1) Semantic `Object' and `Location' grounding that describe function and ambiguous geometries (2) Task specification with an unordered list of goal predicates, and (3) Guiding task recovery with implied scene geometries and trajectory via symmetry cues and configuration space abstraction. Empirical results from four user studies show our interface was much preferred than the control condition, demonstrating high learnability and ease-of-use that enable our non-technical participants to model complex tasks, provide effective recovery assistance, and teleoperative control.
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Date Issued: 2018
Identifier: CFE0007209, ucf:52292
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007209

Title: Multi-Modal Interfaces for Sensemaking of Graph-Connected Datasets.
Creator: Wehrer, Anthony, Hughes, Charles, Wisniewski, Pamela, Pattanaik, Sumanta, Specht, Chelsea, Lisle, Curtis, University of Central Florida
Abstract / Description: The visualization of hypothesized evolutionary processes is often shown through phylogenetic trees. Given evolutionary data presented in one of several widely accepted formats, software exists to render these data into a tree diagram. However, software packages commonly in use by biologists today often do not provide means to dynamically adjust and customize these diagrams for studying new hypothetical relationships, and for illustration and publication purposes. Even where these options are...
Show moreThe visualization of hypothesized evolutionary processes is often shown through phylogenetic trees. Given evolutionary data presented in one of several widely accepted formats, software exists to render these data into a tree diagram. However, software packages commonly in use by biologists today often do not provide means to dynamically adjust and customize these diagrams for studying new hypothetical relationships, and for illustration and publication purposes. Even where these options are available, there can be a lack of intuitiveness and ease-of-use. The goal of our research is, thus, to investigate more natural and effective means of sensemaking of the data with different user input modalities. To this end, we experimented with different input modalities, designing and running a series of prototype studies, ultimately focusing our attention on pen-and-touch. Through several iterations of feedback and revision provided with the help of biology experts and students, we developed a pen-and-touch phylogenetic tree browsing and editing application called PhyloPen. This application expands on the capabilities of existing software with visualization techniques such as overview+detail, linked data views, and new interaction and manipulation techniques using pen-and-touch. To determine its impact on phylogenetic tree sensemaking, we conducted a within-subject comparative summative study against the most comparable and commonly used state-of-the-art mouse-based software system, Mesquite. Conducted with biology majors at the University of Central Florida, each used both software systems on a set number of exercise tasks of the same type. Determining effectiveness by several dependent measures, the results show PhyloPen was significantly better in terms of usefulness, satisfaction, ease-of-learning, ease-of-use, and cognitive load and relatively the same in variation of completion time. These results support an interaction paradigm that is superior to classic mouse-based interaction, which could have the potential to be applied to other communities that employ graph-based representations of their problem domains.
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Date Issued: 2019
Identifier: CFE0007872, ucf:52788
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007872

Title: MARKERLESS TRACKING USING POLAR CORRELATION OF CAMERA OPTICAL FLOW.
Creator: Gupta, Prince, da Vitoria Lobo, Niels, University of Central Florida
Abstract / Description: We present a novel, real-time, markerless vision-based tracking system, employing a rigid orthogonal configuration of two pairs of opposing cameras. Our system uses optical flow over sparse features to overcome the limitation of vision-based systems that require markers or a pre-loaded model of the physical environment. We show how opposing cameras enable cancellation of common components of optical flow leading to an efficient tracking algorithm that captures five degrees of freedom...
Show moreWe present a novel, real-time, markerless vision-based tracking system, employing a rigid orthogonal configuration of two pairs of opposing cameras. Our system uses optical flow over sparse features to overcome the limitation of vision-based systems that require markers or a pre-loaded model of the physical environment. We show how opposing cameras enable cancellation of common components of optical flow leading to an efficient tracking algorithm that captures five degrees of freedom including direction of translation and angular velocity. Experiments comparing our device with an electromagnetic tracker show that its average tracking accuracy is 80% over 185 frames, and it is able to track large range motions even in outdoor settings. We also present how opposing cameras in vision-based inside-looking-out systems can be used for gesture recognition. To demonstrate our approach, we discuss three different algorithms for recovering motion parameters at different levels of complete recovery. We show how optical flow in opposing cameras can be used to recover motion parameters of the multi-camera rig. Experimental results show gesture recognition accuracy of 88.0%, 90.7% and 86.7% for our three techniques, respectively, across a set of 15 gestures.
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Date Issued: 2010
Identifier: CFE0003163, ucf:48611
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0003163

Title: The WOZ Recognizer: A Tool For Understanding User Perceptions of Sketch-Based Interfaces.
Creator: Bott, Jared, Laviola II, Joseph, Hughes, Charles, Foroosh, Hassan, Lank, Edward, University of Central Florida
Abstract / Description: Sketch recognition has the potential to be an important input method for computers in the coming years; however, designing and building an accurate and sophisticated sketch recognition system is a time consuming and daunting task. Since sketch recognition is still at a level where mistakes are common, it is important to understand how users perceive and tolerate recognition errors and other user interface elements with these imperfect systems. A problem in performing this type of research is...
Show moreSketch recognition has the potential to be an important input method for computers in the coming years; however, designing and building an accurate and sophisticated sketch recognition system is a time consuming and daunting task. Since sketch recognition is still at a level where mistakes are common, it is important to understand how users perceive and tolerate recognition errors and other user interface elements with these imperfect systems. A problem in performing this type of research is that we cannot easily control aspects of recognition in order to rigorously study the systems. We performed a study examining user perceptions of three pen-based systems for creating logic gate diagrams: a sketch-based interface, a WIMP-based interface, and a hybrid interface that combined elements of sketching and WIMP. We found that users preferred the sketch-based interface and we identified important criteria for pen-based application design. This work exposed the issue of studying recognition systems without fine-grained control over accuracy, recognition mode, and other recognizer properties. In order to solve this problem, we developed a Wizard of Oz sketch recognition tool, the WOZ Recognizer, that supports controlled symbol and position accuracy and batch and streaming recognition modes for a variety of sketching domains. We present the design of the WOZ Recognizer, modeling recognition domains using graphs, symbol alphabets, and grammars; and discuss the types of recognition errors we included in its design. Further, we discuss how the WOZ Recognizer simulates sketch recognition, controlling the WOZ Recognizer, and how users interact with it. In addition, we present an evaluative user study of the WOZ Recognizer and the lessons we learned.We have used the WOZ Recognizer to perform two user studies examining user perceptions of sketch recognition; both studies focused on mathematical sketching. In the first study, we examined whether users prefer recognition feedback now (real-time recognition) or later (batch recognition) in relation to different recognition accuracies and sketch complexities. We found that participants displayed a preference for real-time recognition in some situations (multiple expressions, low accuracy), but no statistical preference in others. In our second study, we examined whether users displayed a greater tolerance for recognition errors when they used mathematical sketching applications they found interesting or useful compared to applications they found less interesting. Participants felt they had a greater tolerance for the applications they preferred, although our statistical analysis did not positively support this.In addition to the research already performed, we propose several avenues for future research into user perceptions of sketch recognition that we believe will be of value to sketch recognizer researchers and application designers.
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Date Issued: 2016
Identifier: CFE0006077, ucf:50945
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006077

Title: Bridging the Gap Between Fun and Fitness: Instructional Techniques and Real-World Applications for Full-Body Dance Games.
Creator: Charbonneau, Emiko, Laviola II, Joseph, Hughes, Charles, Tappen, Marshall, Angelopoulos, Theodore, Mueller, Florian, University of Central Florida
Abstract / Description: Full-body controlled games offer the opportunity for not only entertainment, but education and exercise as well. Refined gameplay mechanics and content can boost intrinsic motivation and keep people playing over a long period of time, which is desirable for individuals who struggle with maintaining a regular exercise program. Within this gameplay genre, dance rhythm games have proven to be popular with game console owners. Yet, while other types of games utilize story mechanics that keep...
Show moreFull-body controlled games offer the opportunity for not only entertainment, but education and exercise as well. Refined gameplay mechanics and content can boost intrinsic motivation and keep people playing over a long period of time, which is desirable for individuals who struggle with maintaining a regular exercise program. Within this gameplay genre, dance rhythm games have proven to be popular with game console owners. Yet, while other types of games utilize story mechanics that keep players engaged for dozens of hours, motion-controlled dance games are just beginning to incorporate these elements. In addition, this control scheme is still young, only becoming commercially available in the last few years. Instructional displays and clear real-time feedback remain difficult challenges.This thesis investigates the potential for full-body dance games to be used as tools for entertainment, education, and fitness. We built several game prototypes to investigate visual, aural, and tactile methods for instruction and feedback. We also evaluated the fitness potential of the game Dance Central 2 both by itself and with extra game content which unlocked based on performance.Significant contributions include a framework for running a longitudinal video game study, results indicating high engagement with some fitness potential, and informed discussion of how dance games could make exertion a more enjoyable experience.
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Date Issued: 2013
Identifier: CFE0004829, ucf:49690
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004829

Title: DEVELOPMENT OF A GRAPHICAL USER INTERFACE FOR CAL3QHC CALLED CALQCAD.
Creator: Gawalpanchi, Sheetal, Cooper, Charles, University of Central Florida
Abstract / Description: One of the major sources of air pollution in the United States metropolitan areas is due to automobiles. With the huge growth of motor vehicles and, greater dependence on them, air pollution problems have been aggravated. According to the EPA, nearly 95% of carbon monoxide (CO ) (EPA 1999) in urban areas comes from mobile sources, of which 51% is contributed by on road vehicles. It is well known fact that, carbon monoxide is one of the major mobile source pollutants and CO has detrimental...
Show moreOne of the major sources of air pollution in the United States metropolitan areas is due to automobiles. With the huge growth of motor vehicles and, greater dependence on them, air pollution problems have been aggravated. According to the EPA, nearly 95% of carbon monoxide (CO ) (EPA 1999) in urban areas comes from mobile sources, of which 51% is contributed by on road vehicles. It is well known fact that, carbon monoxide is one of the major mobile source pollutants and CO has detrimental effects on the human health. Carbon monoxide is the result of mainly incomplete combustion of gasoline in motor vehicles (FDOT 1996). The National Environmental Policy Act (NEPA) gives important considerations to the actions to be taken. Transportation conformity . The Clean Air Act Amendments (CAAA, 1970) was an important step in meeting the National Ambient Air Quality Standards In order to evaluate the effects of CO and Particulate Matter (PM) impacts based on the criteria for NAAQS standards, it is necessary to conduct dispersion modeling of emissions for mobile source emissions. Design of transportation engineering systems (roadway design) should take care of both the flow of the traffic as well as the air pollution aspects involved. Roadway projects need to conform to the State Implementation Plan (SIP) and meet the NAAQS. EPA guidelines for air quality modeling on such roadway intersections recommend the use of CAL3QHC. The model has embedded in it CALINE 3.0 (Benson 1979) – a line source dispersion model based on the Gaussian equation. The model requires parameters with respect to the roadway geometry, fleet volume, averaging time, surface roughness, emission factors, etc. The CAL3QHC model is a DOS based model which requires the modeling parameters to be fed into an input file. The creation of input the file is a tedious job. Previous work at UCF, resulted in the development of CALQVIEW, which expedites this process of creating input files, but the task of extracting the coordinates still has to be done manually. The main aim of the thesis is to reduce the analysis time for modeling emissions from roadway intersections, by expediting the process of extracting the coordinates required for the CAL3QHC model. Normally, transportation engineers design and model intersections for the traffic flow utilizing tools such as AutoCAD, Microstation etc. This thesis was to develop advanced software allowing graphical editing and coordinates capturing from an AutoCAD file. This software was named as CALQCAD. This advanced version will enable the air quality analyst to capture the coordinates from an AutoCAD 2004 file. This should expedite the process of modeling intersections and decrease analyst time from a few days to few hours. The model helps to assure the air quality analyst to retain accuracy during the modeling process. The idea to create the standalone interface was to give the AutoCAD user full functionality of AutoCAD tools in case editing is required to the main drawing. It also provides the modeler with a separate graphical user interface (GUI).
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Date Issued: 2005
Identifier: CFE0000483, ucf:46364
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0000483

Title: OPTIMIZING THE DESIGN OF MULTIMODAL USER INTERFACES.
Creator: Reeves, Leah, Stanney, Kay, University of Central Florida
Abstract / Description: Due to a current lack of principle-driven multimodal user interface design guidelines, designers may encounter difficulties when choosing the most appropriate display modality for given users or specific tasks (e.g., verbal versus spatial tasks). The development of multimodal display guidelines from both a user and task domain perspective is thus critical to the achievement of successful human-system interaction. Specifically, there is a need to determine how to design task information...
Show moreDue to a current lack of principle-driven multimodal user interface design guidelines, designers may encounter difficulties when choosing the most appropriate display modality for given users or specific tasks (e.g., verbal versus spatial tasks). The development of multimodal display guidelines from both a user and task domain perspective is thus critical to the achievement of successful human-system interaction. Specifically, there is a need to determine how to design task information presentation (e.g., via which modalities) to capitalize on an individual operator's information processing capabilities and the inherent efficiencies associated with redundant sensory information, thereby alleviating information overload. The present effort addresses this issue by proposing a theoretical framework (Architecture for Multi-Modal Optimization, AMMO) from which multimodal display design guidelines and adaptive automation strategies may be derived. The foundation of the proposed framework is based on extending, at a functional working memory (WM) level, existing information processing theories and models with the latest findings in cognitive psychology, neuroscience, and other allied sciences. The utility of AMMO lies in its ability to provide designers with strategies for directing system design, as well as dynamic adaptation strategies (i.e., multimodal mitigation strategies) in support of real-time operations. In an effort to validate specific components of AMMO, a subset of AMMO-derived multimodal design guidelines was evaluated with a simulated weapons control system multitasking environment. The results of this study demonstrated significant performance improvements in user response time and accuracy when multimodal display cues were used (i.e., auditory and tactile, individually and in combination) to augment the visual display of information, thereby distributing human information processing resources across multiple sensory and WM resources. These results provide initial empirical support for validation of the overall AMMO model and a sub-set of the principle-driven multimodal design guidelines derived from it. The empirically-validated multimodal design guidelines may be applicable to a wide range of information-intensive computer-based multitasking environments.
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Date Issued: 2007
Identifier: CFE0001636, ucf:47237
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001636

Title: PATCHWORK CULTURE: QUILT TACTICS AND DIGITEXTUALITY.
Creator: Barrett Ferrier, Michelle, Saper, Craig, University of Central Florida
Abstract / Description: Embedded in the quilt top, the fabric patches are relays, time pathways to stories and memories of their former owners. Through the quilts, the voices of the past survive. The stories trace a path of connection between oral traditions, storytelling, the invention of meaning, and the preservation of cultural memory. The theory and method described herein use the quilt patchwork metaphor as the basis for a web interface for designing and modeling knowledge-based graphical, narrative, and...
Show moreEmbedded in the quilt top, the fabric patches are relays, time pathways to stories and memories of their former owners. Through the quilts, the voices of the past survive. The stories trace a path of connection between oral traditions, storytelling, the invention of meaning, and the preservation of cultural memory. The theory and method described herein use the quilt patchwork metaphor as the basis for a web interface for designing and modeling knowledge-based graphical, narrative, and multimedia data. More specifically, the method comprises a digital storytelling and knowledge management tool that allows one or more users to create, save, store, and visually map or model digital stories. The method creates a digital network of a community's stories for digital ethnography work. Digital patches that represent the gateway to the stories of an individual are pieced together into a larger quilt design, creating a visual space that yields the voices of its creators at the click of a mouse. Through this narrative mapping, users are able to deal with complexity, ambiguity, density, and information overload. The method takes the traditional quilt use and appropriates it into a digital apparatus so that the user is connected to multiple points of view that can be dynamically tried out and compared. The hypertextual quilting method fulfills the definition of a deconstructive hypertext and emancipatory social science research methodologies by creating a collaborative, polyvocal interface where users have access to the code, content and conduits to rewrite culture's history with subaltern voices. In this digital place of intertextuality, stories are juxtaposed with images in a montage that denies the authority of a single voice and refuses fixed meaning. In dialogue, contestation, and play, the digitextuality of the Digital Story Quilt provides a praxis for critical theory. The Digital Story Quilt method concerns itself with questions of identity, the processes through which these identities are developed, the mechanics of processes of privilege and marginalization and the possibility of political action through narrative performance against these processes.
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Date Issued: 2007
Identifier: CFE0001659, ucf:47239
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001659

Title: Developing surface engineered liquid crystal droplets for sensing applications.
Creator: Bera, Tanmay, Fang, Jiyu, Suryanarayana, Challapalli, Huo, Qun, Cho, Hyong, Deng, Weiwei, Wu, Shintson, University of Central Florida
Abstract / Description: Diagnosis plays a very crucial role in medicine and health care, which makes biosensors extremely important in modern technological context. Till date, various types of biosensors have been developed that are capable of detecting a wide range of biologically important species with great sensitivity and selectivity. However, most of these sensing units require highly sophisticated instrumentation and often lack the desired portability. Liquid crystal (LC) droplets, on the other hand, are a new...
Show moreDiagnosis plays a very crucial role in medicine and health care, which makes biosensors extremely important in modern technological context. Till date, various types of biosensors have been developed that are capable of detecting a wide range of biologically important species with great sensitivity and selectivity. However, most of these sensing units require highly sophisticated instrumentation and often lack the desired portability. Liquid crystal (LC) droplets, on the other hand, are a new type of functional material that are finding increasing research attention as a new sensing unit due to their tunable optical property, high surface area, portability and cost-effectiveness. In this dissertation, functionalized LC droplets for biosensing at aqueous-LC interface are highlighted. Chemically functionalized LC droplets dispersed in aqueous solution were prepared by the self-assembly of amphiphilic molecules at the aqueous/LC interface. These functionalized LC droplets showed a well-defined director of configuration and a specific optical pattern when observed with a polarizing light microscope. It was discovered that the interaction of chemically functionalized LC droplets with an analyte triggers transition of the director of configuration of the LC within the droplets, providing a simple and unique optical sign for the detection of the analyte. Moreover, the director of configuration transition happened in a concentration dependent manner, allowing both qualitative and quantitative detection of the analyte. The sensitivity of chemically functionalized LC droplets depends not only on the nature of amphiphilic molecules but also the size and number of the droplets.The dissertation essentially deals with the application of these chemically functionalized LC droplets in detecting several biologically important species. It was observed that the adsorption of charged macromolecules (dendrimers, proteins, and viruses) on polyelectrolyte functionalized LC droplets triggered a bipolar-to-radial configuration transition based on the polar verses non-polar interaction. By using a simple optical microscope, microgram per milliliter concentrations of bovine serum albumin, cowpea mosaic virus, and tobacco mosaic virus could be detected in aqueous solution. The detection limit of Mastoparan X polypeptide decorated LC droplets in detecting E. coli could reach to approximately 10 bacteria per milliliter. In this case, the high affinity of the polypeptide towards the bacterial causes the former to detach from the LC droplets, triggering the director of configuration transition of the LC inside the droplets. Finally, surfactant decorated LC droplets were used to detect lithocholic acid (LCA), a toxic bile acid used as a specific biomarker for colon cancers. In this case, the director of configuration transition of the LC inside the droplets is a result of the replacement of the surfactant from the aqueous/LC interface by LCA. The microgram per milliliter concentration of LCA, a clinically significant concentration, could be easily detected by changing the length of surfactants. These studies highlight the novel use of surface functionalized LC droplets to detect biologically important species. Due to their tunable optical property, coupled with high surface area and portability, surface functionalized LC droplets have great potentials in the design of next generation biosensors.
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Date Issued: 2012
Identifier: CFE0004307, ucf:49471
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004307

Title: The Impact of User-Generated Interfaces on the Participation of Users with a Disability in Virtual Environments: Blizzard Entertainment's World of Warcraft Model.
Creator: Merritt, Donald, McDaniel, Rudy, Zemliansky, Pavel, Mauer, Barry, Kim, Si Jung, University of Central Florida
Abstract / Description: When discussing games and the experience of gamers those with disabilities are often overlooked. This has left a gap in our understanding of the experience of players with disabilities in virtual game worlds. However there are examples of players with disabilities being very successful in the virtual world video game World of Warcraft, suggesting that there is an opportunity to study the game for usability insight in creating other virtual world environments. This study surveyed World of...
Show moreWhen discussing games and the experience of gamers those with disabilities are often overlooked. This has left a gap in our understanding of the experience of players with disabilities in virtual game worlds. However there are examples of players with disabilities being very successful in the virtual world video game World of Warcraft, suggesting that there is an opportunity to study the game for usability insight in creating other virtual world environments. This study surveyed World of Warcraft players with disabilities online for insight into how they used interface addons to manage their experience and identity performance in the game. A rubric was also created to study a selection of addons for evidence of the principles of Universal Design for Learning (UDL). The study found that World of Warcraft players with disabilities do not use addons more than able-bodied players, but some of the most popular addons do exhibit many or most of the principles of UDL. UDL principles appear to have emerged organically from addon iterations over time. The study concludes by suggesting that the same approach to user-generated content for the game interface taken by the creators of World of Warcraft, as well as high user investment in the environment, can lead to more accessible virtual world learning environments in the future.
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Date Issued: 2015
Identifier: CFE0005667, ucf:50175
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005667

Title: Human-Robot Interaction For Multi-Robot Systems.
Creator: Lewis, Bennie, Sukthankar, Gita, Hughes, Charles, Laviola II, Joseph, Boloni, Ladislau, Hancock, Peter, University of Central Florida
Abstract / Description: Designing an effective human-robot interaction paradigm is particularly important for complex tasks such as multi robot manipulation that require the human and robot to work together in a tightly coupled fashion. Although increasing the number of robots can expand the area that therobots can cover within a bounded period of time, a poor human-robot interface will ultimately compromise the performance of the team of robots. However, introducing a human operator to the team of robots, does not...
Show moreDesigning an effective human-robot interaction paradigm is particularly important for complex tasks such as multi robot manipulation that require the human and robot to work together in a tightly coupled fashion. Although increasing the number of robots can expand the area that therobots can cover within a bounded period of time, a poor human-robot interface will ultimately compromise the performance of the team of robots. However, introducing a human operator to the team of robots, does not automatically improve performance due to the difficulty of teleoperating mobile robots with manipulators. The human operator's concentration is divided not only amongmultiple robots but also between controlling each robot's base and arm. This complexity substantially increases the potential neglect time, since the operator's inability to effectively attend to each robot during a critical phase of the task leads to a significant degradation in task performance.There are several proven paradigms for increasing the efficacy of human-robot interaction: 1) multimodal interfaces in which the user controls the robots using voice and gesture; 2) configurable interfaces which allow the user to create new commands by demonstrating them; 3) adaptive interfaceswhich reduce the operator's workload as necessary through increasing robot autonomy. This dissertation presents an evaluation of the relative benefits of different types of user interfaces for multi-robot systems composed of robots with wheeled bases and three degree of freedom arms. It describes a design for constructing low-cost multi-robot manipulation systems from off the shelfparts.User expertise was measured along three axes (navigation, manipulation, and coordination), and participants who performed above threshold on two out of three dimensions on a calibration task were rated as expert. Our experiments reveal that the relative expertise of the user was the key determinant of the best performing interface paradigm for that user, indicating that good user modeling is essential for designing a human-robot interaction system that will be used for an extended period of time. The contributions of the dissertation include: 1) a model for detecting operator distraction from robot motion trajectories; 2) adjustable autonomy paradigms for reducing operator workload; 3) a method for creating coordinated multi-robot behaviors from demonstrations with a single robot; 4) a user modeling approach for identifying expert-novice differences from short teleoperation traces.
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Date Issued: 2014
Identifier: CFE0005198, ucf:50613
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005198

Title: BUSINESS CASE STUDIES IN SUSTAINABILITY PRACTICES.
Creator: Lynch, Sheri L, Combs, James G., University of Central Florida
Abstract / Description: Protecting the environment for future generations is crucial. Although businesses are under strong pressure to support sustainability, many leaders find it challenging to meet the environmental needs of the present without negatively impacting their economic goals. This paper describes some methods that businesses have adopted to effectively manage environmental issues and offer an opportunity for competitive advantage. In particular, three case studies show ways that the companies have...
Show moreProtecting the environment for future generations is crucial. Although businesses are under strong pressure to support sustainability, many leaders find it challenging to meet the environmental needs of the present without negatively impacting their economic goals. This paper describes some methods that businesses have adopted to effectively manage environmental issues and offer an opportunity for competitive advantage. In particular, three case studies show ways that the companies have embraced and integrated sustainability into their strategic planning process, which helped them achieve growth and success in the context of social and environmental concerns. The paper shows how these businesses have chosen to embrace sustainability to minimize the negative impact in our environment, society, and economy. The case studies can help managers define and prioritize their sustainability goals, achieve social and economic value, and transform these environmental investments into sources of competitive advantage. This paper can be beneficial to other businesses who desire to move beyond compliance of the law and become proactive in helping our environment for future generations.
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Date Issued: 2016
Identifier: CFH2000100, ucf:45523
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFH2000100

Title: EPISODIC MEMORY MODEL FOR EMBODIED CONVERSATIONAL AGENTS.
Creator: Elvir, Miguel, Gonzalez, Avelino, University of Central Florida
Abstract / Description: Embodied Conversational Agents (ECA) form part of a range of virtual characters whose intended purpose include engaging in natural conversations with human users. While works in literature are ripe with descriptions of attempts at producing viable ECA architectures, few authors have addressed the role of episodic memory models in conversational agents. This form of memory, which provides a sense of autobiographic record-keeping in humans, has only recently been peripherally integrated into...
Show moreEmbodied Conversational Agents (ECA) form part of a range of virtual characters whose intended purpose include engaging in natural conversations with human users. While works in literature are ripe with descriptions of attempts at producing viable ECA architectures, few authors have addressed the role of episodic memory models in conversational agents. This form of memory, which provides a sense of autobiographic record-keeping in humans, has only recently been peripherally integrated into dialog management tools for ECAs. In our work, we propose to take a closer look at the shared characteristics of episodic memory models in recent examples from the field. Additionally, we propose several enhancements to these existing models through a unified episodic memory model for ECAÃ‚Â's. As part of our research into episodic memory models, we present a process for determining the prevalent contexts in the conversations obtained from the aforementioned interactions. The process presented demonstrates the use of statistical and machine learning services, as well as Natural Language Processing techniques to extract relevant snippets from conversations. Finally, mechanisms to store, retrieve, and recall episodes from previous conversations are discussed. A primary contribution of this research is in the context of contemporary memory models for conversational agents and cognitive architectures. To the best of our knowledge, this is the first attempt at providing a comparative summary of existing works. As implementations of ECAs become more complex and encompass more realistic conversation engines, we expect that episodic memory models will continue to evolve and further enhance the naturalness of conversations.
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Date Issued: 2010
Identifier: CFE0003353, ucf:48443
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0003353

Title: Biophysical Sources of 1/f Noises in Neurological Systems.
Creator: Paris, Alan, Vosoughi, Azadeh, Atia, George, Wiegand, Rudolf, Douglas, Pamela, Berman, Steven, University of Central Florida
Abstract / Description: High levels of random noise are a defining characteristic of neurological signals at all levels, from individual neurons up to electroencephalograms (EEG). These random signals degrade the performance of many methods of neuroengineering and medical neuroscience. Understanding this noise also is essential for applications such as real-time brain-computer interfaces (BCIs), which must make accurate control decisions from very short data epochs. The major type of neurological noise is of the so...
Show moreHigh levels of random noise are a defining characteristic of neurological signals at all levels, from individual neurons up to electroencephalograms (EEG). These random signals degrade the performance of many methods of neuroengineering and medical neuroscience. Understanding this noise also is essential for applications such as real-time brain-computer interfaces (BCIs), which must make accurate control decisions from very short data epochs. The major type of neurological noise is of the so-called 1/f-type, whose origins and statistical nature has remained unexplained for decades. This research provides the first simple explanation of 1/f-type neurological noise based on biophysical fundamentals. In addition, noise models derived from this theory provide validated algorithm performance improvements over alternatives.Specifically, this research defines a new class of formal latent-variable stochastic processes called hidden quantum models (HQMs) which clarify the theoretical foundations of ion channel signal processing. HQMs are based on quantum state processes which formalize time-dependent observation. They allow the quantum-based calculation of channel conductance autocovariance functions, essential for frequency-domain signal processing. HQMs based on a particular type of observation protocol called independent activated measurements are shown to be distributionally equivalent to hidden Markov models yet without an underlying physical Markov process. Since the formal Markov processes are non-physical, the theory of activated measurement allows merging energy-based Eyring rate theories of ion channel behavior with the more common phenomenological Markov kinetic schemes to form energy-modulated quantum channels. These unique biophysical concepts developed to understand the mechanisms of ion channel kinetics have the potential of revolutionizing our understanding of neurological computation.To apply this theory, the simplest quantum channel model consistent with neuronal membrane voltage-clamp experiments is used to derive the activation eigenenergies for the Hodgkin-Huxley K+ and Na+ ion channels. It is shown that maximizing entropy under constrained activation energy yields noise spectral densities approximating S(f) = 1/f, thus offering a biophysical explanation for this ubiquitous noise component. These new channel-based noise processes are called generalized van der Ziel-McWhorter (GVZM) power spectral densities (PSDs). This is the only known EEG noise model that has a small, fixed number of parameters, matches recorded EEG PSD's with high accuracy from 0 Hz to over 30 Hz without infinities, and has approximately 1/f behavior in the mid-frequencies. In addition to the theoretical derivation of the noise statistics from ion channel stochastic processes, the GVZM model is validated in two ways. First, a class of mixed autoregressive models is presented which simulate brain background noise and whose periodograms are proven to be asymptotic to the GVZM PSD. Second, it is shown that pairwise comparisons of GVZM-based algorithms, using real EEG data from a publicly-available data set, exhibit statistically significant accuracy improvement over two well-known and widely-used steady-state visual evoked potential (SSVEP) estimators.
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Date Issued: 2016
Identifier: CFE0006485, ucf:51418
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006485

Title: Nonlinear dynamic modeling, simulation and characterization of the mesoscale neuron-electrode interface.
Creator: Thakore, Vaibhav, Hickman, James, Mucciolo, Eduardo, Rahman, Talat, Johnson, Michael, Behal, Aman, Molnar, Peter, University of Central Florida
Abstract / Description: Extracellular neuroelectronic interfacing has important applications in the fields of neural prosthetics, biological computation and whole-cell biosensing for drug screening and toxin detection. While the field of neuroelectronic interfacing holds great promise, the recording of high-fidelity signals from extracellular devices has long suffered from the problem of low signal-to-noise ratios and changes in signal shapes due to the presence of highly dispersive dielectric medium in the neuron...
Show moreExtracellular neuroelectronic interfacing has important applications in the fields of neural prosthetics, biological computation and whole-cell biosensing for drug screening and toxin detection. While the field of neuroelectronic interfacing holds great promise, the recording of high-fidelity signals from extracellular devices has long suffered from the problem of low signal-to-noise ratios and changes in signal shapes due to the presence of highly dispersive dielectric medium in the neuron-microelectrode cleft. This has made it difficult to correlate the extracellularly recorded signals with the intracellular signals recorded using conventional patch-clamp electrophysiology. For bringing about an improvement in the signal-to-noise ratio of the signals recorded on the extracellular microelectrodes and to explore strategies for engineering the neuron-electrode interface there exists a need to model, simulate and characterize the cell-sensor interface to better understand the mechanism of signal transduction across the interface. Efforts to date for modeling the neuron-electrode interface have primarily focused on the use of point or area contact linear equivalent circuit models for a description of the interface with an assumption of passive linearity for the dynamics of the interfacial medium in the cell-electrode cleft. In this dissertation, results are presented from a nonlinear dynamic characterization of the neuroelectronic junction based on Volterra-Wiener modeling which showed that the process of signal transduction at the interface may have nonlinear contributions from the interfacial medium. An optimization based study of linear equivalent circuit models for representing signals recorded at the neuron-electrode interface subsequently proved conclusively that the process of signal transduction across the interface is indeed nonlinear. Following this a theoretical framework for the extraction of the complex nonlinear material parameters of the interfacial medium like the dielectric permittivity, conductivity and diffusivity tensors based on dynamic nonlinear Volterra-Wiener modeling was developed. Within this framework, the use of Gaussian bandlimited white noise for nonlinear impedance spectroscopy was shown to offer considerable advantages over the use of sinusoidal inputs for nonlinear harmonic analysis currently employed in impedance characterization of nonlinear electrochemical systems. Signal transduction at the neuron-microelectrode interface is mediated by the interfacial medium confined to a thin cleft with thickness on the scale of 20-110 nm giving rise to Knudsen numbers (ratio of mean free path to characteristic system length) in the range of 0.015 and 0.003 for ionic electrodiffusion. At these Knudsen numbers, the continuum assumptions made in the use of Poisson-Nernst-Planck system of equations for modeling ionic electrodiffusion are not valid. Therefore, a lattice Boltzmann method (LBM) based multiphysics solver suitable for modeling ionic electrodiffusion at the mesoscale neuron-microelectrode interface was developed. Additionally, a molecular speed dependent relaxation time was proposed for use in the lattice Boltzmann equation. Such a relaxation time holds promise for enhancing the numerical stability of lattice Boltzmann algorithms as it helped recover a physically correct description of microscopic phenomena related to particle collisions governed by their local density on the lattice. Next, using this multiphysics solver simulations were carried out for the charge relaxation dynamics of an electrolytic nanocapacitor with the intention of ultimately employing it for a simulation of the capacitive coupling between the neuron and the planar microelectrode on a microelectrode array (MEA). Simulations of the charge relaxation dynamics for a step potential applied at t = 0 to the capacitor electrodes were carried out for varying conditions of electric double layer (EDL) overlap, solvent viscosity, electrode spacing and ratio of cation to anion diffusivity. For a large EDL overlap, an anomalous plasma-like collective behavior of oscillating ions at a frequency much lower than the plasma frequency of the electrolyte was observed and as such it appears to be purely an effect of nanoscale confinement. Results from these simulations are then discussed in the context of the dynamics of the interfacial medium in the neuron-microelectrode cleft. In conclusion, a synergistic approach to engineering the neuron-microelectrode interface is outlined through a use of the nonlinear dynamic modeling, simulation and characterization tools developed as part of this dissertation research.
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Date Issued: 2012
Identifier: CFE0004797, ucf:49718
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004797

Title: Exploring 3D User Interface Technologies for Improving the Gaming Experience.
Creator: Kulshreshth, Arun, Laviola II, Joseph, Hughes, Charles, Da Vitoria Lobo, Niels, Masuch, Maic, University of Central Florida
Abstract / Description: 3D user interface technologies have the potential to make games more immersive (&) engaging and thus potentially provide a better user experience to gamers. Although 3D user interface technologies are available for games, it is still unclear how their usage affects game play and if there are any user performance benefits. A systematic study of these technologies in game environments is required to understand how game play is affected and how we can optimize the usage in order to achieve...
Show more3D user interface technologies have the potential to make games more immersive (&) engaging and thus potentially provide a better user experience to gamers. Although 3D user interface technologies are available for games, it is still unclear how their usage affects game play and if there are any user performance benefits. A systematic study of these technologies in game environments is required to understand how game play is affected and how we can optimize the usage in order to achieve better game play experience.This dissertation seeks to improve the gaming experience by exploring several 3DUI technologies. In this work, we focused on stereoscopic 3D viewing (to improve viewing experience) coupled with motion based control, head tracking (to make games more engaging), and faster gesture based menu selection (to reduce cognitive burden associated with menu interaction while playing). We first studied each of these technologies in isolation to understand their benefits for games. We present the results of our experiments to evaluate benefits of stereoscopic 3D (when coupled with motion based control) and head tracking in games. We discuss the reasons behind these findings and provide recommendations for game designers who want to make use of these technologies to enhance gaming experiences. We also present the results of our experiments with finger-based menu selection techniques with an aim to find out the fastest technique. Based on these findings, we custom designed an air-combat game prototype which simultaneously uses stereoscopic 3D, head tracking, and finger-count shortcuts to prove that these technologies could be useful for games if the game is designed with these technologies in mind. Additionally, to enhance depth discrimination and minimize visual discomfort, the game dynamically optimizes stereoscopic 3D parameters (convergence and separation) based on the user's look direction. We conducted a within subjects experiment where we examined performance data and self-reported data on users perception of the game. Our results indicate that participants performed significantly better when all the 3DUI technologies (stereoscopic 3D, head-tracking and finger-count gestures) were available simultaneously with head tracking as a dominant factor. We explore the individual contribution of each of these technologies to the overall gaming experience and discuss the reasons behind our findings.Our experiments indicate that 3D user interface technologies could make gaming experience better if used effectively. The games must be designed to make use of the 3D user interface technologies available in order to provide a better gaming experience to the user. We explored a few technologies as part of this work and obtained some design guidelines for future game designers. We hope that our work will serve as the framework for the future explorations of making games better using 3D user interface technologies.
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Date Issued: 2015
Identifier: CFE0005643, ucf:50190
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005643

Title: Facilitating Information Retrieval in Social Media User Interfaces.
Creator: Costello, Anthony, Tang, Yubo, Fiore, Stephen, Goldiez, Brian, University of Central Florida
Abstract / Description: As the amount of computer mediated information (e.g., emails, documents, multi-media) we need to process grows, our need to rapidly sort, organize and store electronic information likewise increases. In order to store information effectively, we must find ways to sort through it and organize it in a manner that facilitates efficient retrieval. The instantaneous and emergent nature of communications across networks like Twitter makes them suitable for discussing events (e.g., natural disasters...
Show moreAs the amount of computer mediated information (e.g., emails, documents, multi-media) we need to process grows, our need to rapidly sort, organize and store electronic information likewise increases. In order to store information effectively, we must find ways to sort through it and organize it in a manner that facilitates efficient retrieval. The instantaneous and emergent nature of communications across networks like Twitter makes them suitable for discussing events (e.g., natural disasters) that are amorphous and prone to rapid changes. It can be difficult for an individual human to filter through and organize the large amounts of information that can pass through these types of social networks when events are unfolding rapidly. A common feature of social networks is the images (e.g., human faces, inanimate objects) that are often used by those who send messages across these networks. Humans have a particularly strong ability to recognize and differentiate between human Faces. This effect may also extend to recalling information associated with each human Face. This study investigated the difference between human Face images, non-human Face images and alphanumeric labels as retrieval cues under different levels of Task Load. Participants were required to recall key pieces of event information as they emerged from a Twitter-style message feed during a simulated natural disaster. A counter-balanced within-subjects design was used for this experiment. Participants were exposed to low, medium and high Task Load while responding to five different types of recall cues: (1) Nickname, (2) Non-Face, (3) Non-Face (&) Nickname, (4) Face and (5) Face (&) Nickname. The task required participants to organize information regarding emergencies (e.g., car accidents) from a Twitter-style message feed. The messages reported various events such as fires occurring around a fictional city. Each message was associated with a different recall cue type, depending on the experimental condition. Following the task, participants were asked to recall the information associated with one of the cues they worked with during the task. Results indicate that under medium and high Task Load, both Non-Face and Face retrieval cues increased recall performance over Nickname alone with Non-Faces resulting in the highest mean recall scores. When comparing medium to high Task Load: Face (&) Nickname and Non-Face significantly outperformed the Face condition. The performance in Non-Face (&) Nickname was significantly better than Face (&) Nickname. No significant difference was found between Non-Faces and Non-Faces (&) Nickname. Subjective Task Load scores indicate that participants experienced lower mental workload when using Non-Face cues than using Nickname or Face cues. Generally, these results indicate that under medium and high Task Load levels, images outperformed alphanumeric nicknames, Non-Face images outperformed Face images, and combining alphanumeric nicknames with images may have offered a significant performance advantage only when the image is that of a Face. Both theoretical and practical design implications are provided from these findings.
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Date Issued: 2014
Identifier: CFE0005318, ucf:50524
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005318

Title: Adaptive Architectural Strategies for Resilient Energy-Aware Computing.
Creator: Ashraf, Rizwan, DeMara, Ronald, Lin, Mingjie, Wang, Jun, Jha, Sumit, Johnson, Mark, University of Central Florida
Abstract / Description: Reconfigurable logic or Field-Programmable Gate Array (FPGA) devices have the ability to dynamically adapt the computational circuit based on user-specified or operating-condition requirements. Such hardware platforms are utilized in this dissertation to develop adaptive techniques for achieving reliable and sustainable operation while autonomously meeting these requirements. In particular, the properties of resource uniformity and in-field reconfiguration via on-chip processors are exploited...
Show moreReconfigurable logic or Field-Programmable Gate Array (FPGA) devices have the ability to dynamically adapt the computational circuit based on user-specified or operating-condition requirements. Such hardware platforms are utilized in this dissertation to develop adaptive techniques for achieving reliable and sustainable operation while autonomously meeting these requirements. In particular, the properties of resource uniformity and in-field reconfiguration via on-chip processors are exploited to implement Evolvable Hardware (EHW). EHW utilize genetic algorithms to realize logic circuits at runtime, as directed by the objective function. However, the size of problems solved using EHW as compared with traditional approaches has been limited to relatively compact circuits. This is due to the increase in complexity of the genetic algorithm with increase in circuit size. To address this research challenge of scalability, the Netlist-Driven Evolutionary Refurbishment (NDER) technique was designed and implemented herein to enable on-the-fly permanent fault mitigation in FPGA circuits. NDER has been shown to achieve refurbishment of relatively large sized benchmark circuits as compared to related works. Additionally, Design Diversity (DD) techniques which are used to aid such evolutionary refurbishment techniques are also proposed and the efficacy of various DD techniques is quantified and evaluated.Similarly, there exists a growing need for adaptable logic datapaths in custom-designed nanometer-scale ICs, for ensuring operational reliability in the presence of Process, Voltage, and Temperature (PVT) and, transistor-aging variations owing to decreased feature sizes for electronic devices. Without such adaptability, excessive design guardbands are required to maintain the desired integration and performance levels. To address these challenges, the circuit-level technique of Self-Recovery Enabled Logic (SREL) was designed herein. At design-time, vulnerable portions of the circuit identified using conventional Electronic Design Automation tools are replicated to provide post-fabrication adaptability via intelligent techniques. In-situ timing sensors are utilized in a feedback loop to activate suitable datapaths based on current conditions that optimize performance and energy consumption. Primarily, SREL is able to mitigate the timing degradations caused due to transistor aging effects in sub-micron devices by reducing the stress induced on active elements by utilizing power-gating. As a result, fewer guardbands need to be included to achieve comparable performance levels which leads to considerable energy savings over the operational lifetime.The need for energy-efficient operation in current computing systems has given rise to Near-Threshold Computing as opposed to the conventional approach of operating devices at nominal voltage. In particular, the goal of exascale computing initiative in High Performance Computing (HPC) is to achieve 1 EFLOPS under the power budget of 20MW. However, it comes at the cost of increased reliability concerns, such as the increase in performance variations and soft errors. This has given rise to increased resiliency requirements for HPC applications in terms of ensuring functionality within given error thresholds while operating at lower voltages. My dissertation research devised techniques and tools to quantify the effects of radiation-induced transient faults in distributed applications on large-scale systems. A combination of compiler-level code transformation and instrumentation are employed for runtime monitoring to assess the speed and depth of application state corruption as a result of fault injection. Finally, fault propagation models are derived for each HPC application that can be used to estimate the number of corrupted memory locations at runtime. Additionally, the tradeoffs between performance and vulnerability and the causal relations between compiler optimization and application vulnerability are investigated.
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Date Issued: 2015
Identifier: CFE0006206, ucf:52889
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006206

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